Sotjnd-reprodttcing diaphragm



P. B. DELANY. SOUND REPRODUCING DIAPHRAGM. APPHCATION mm ocr. 1920.

W/gVENTOR M AITORNE UNITED STATES PATENT oFricE.

PATRICK B. DELANY, OF SOUTH ORANGE, NEW JERSEY.

SOUND-REPRODUCING DIAPHRAGM. I

Specification of Letters Patent. Patent-ed 17,- 1922.

Application filed October 1, 1920. Serial No. 414,112.

and claimed a laminated diaphra consist in'g of layers of paper or otherbr'ous-m'aterial alternating with-layers'of permanently flexibleadhesive material, the whole assemblage being' clampe'd between rigid ornonyielding gasket members. Diaphragms of this type have given eatlyimproved results as compared with the ordinary mica diaphragmparticularly in the excellence of rendition of musical tonesunaccompanied by extraneous metallic sounds characteristic of the use ofmica diaphragms. In the course of continued experiments conducted forthe purpose of obtaining, if possible, still more perfect results, Ihave discovered that a greatly improved laminated diaphragm can beformed of layers of fibrous or other material alternating with layers ofa viscous substance, such as Vaseline, in which the factor ofadhesiveness is largely replaced by a lubricating characteristic andwhich not only permanently retains a pronounced yielding or pliantcapacity but also renders the diaphragm, as a whole, impervious tomoisture.

I do not confine myself to the use of any specific material to theexclusion of other materials and I find that excellent results can beobtained by the use of layers of mica, metal or glass alternating withfilms of vaseline, castor oil or other similar materials of animal,vegetable or mineral origin, or combinations of such materials, theassembled diaphragm being clamped between yielding gaskets. When sheetsof fibrous material alternating with viscous substances are used, Iprefer to clamp the diaphragm formed between non-yielding gaskets ofmetal, hard rubber, celluloid or the like. I find that diaphragms ofeither one of the two general forms referred to are greatly superior tothe ordinary solid disk diaphragm formed of mica. in that the normalresonance and metallic ring of the ordinary diaphragm are whollyovercome,

there is almosta complete eliinination of scratching andother-extraneous sounds. In addition, .there is v developed amarkedmellowness and human quality. to vocal tones and a harmonious blendingof svmpathy. in- I strumentation. I t

I attribute-the-superior results. obtained to an increased degree-offlexibility of the thin layers of nateria'l between whicln the materialto, at least, prevent the absorption of moisture by the disks.

In order to exclude air from the viscous substance between the diskscomprising the diaphragm, I arrange to clamp the disks together tightlyat their central as well as at their peripheral portions. thereby anannular air-tight receptacle or series of receptacles for the substanceas will be clear, and which will preserve the material for an indefinite period of time unimpaired.

In the drawing:

Fig. 1 shows in cross-section a diaphragm formed of two disks of thinmica with an interposed layer of viscous lubricating material.

Fig. 2 shows a similar view of a diaphragm formed of four layers ofpaper alternating with lubricating material.

Fig. 3 shows a composite diaphragm such as is shown in either Fig. 1 or2, clamped to gether both at the center and at the periphi ig. 4 shows acomposite diaphragm formed of sheets of fibrous material placed inimmediate contact with each other.

In Fig. 1 of the drawing there is illustrated a diaphragm formed of twothin sheets of mica 1, with an interposed layer of lubricating material2, such as Vaseline. Fig. .2 shows a similar structure in which sheetsof paper 3 or other fibrous material vibrating arm of .viscoussubstance, is .spre'adiand the conse- -quent.damping. of inherentresonance the -case of mineral? or hand; disksas well as to theincreased flexizlziillity 'owingto the lubricationEqfithe' disks,.ingthei-rfbowed flenation. under :thef-actionwt 1 the alternate withfilms of Vaseline 2. I have found a tough-fibred writi paper or .WEZLP-ping paper well adapted? this purpose. As has been already indicated,the composite diaphragm thus produced is much more pliable and sensitivethan a solid diaphragm of the same thickness, owin' to the freedom ofmovement of the disks re ative to each other as contrasted with thestrains and compres sion efi'ects on the outer surfaces of the solid orunitary type of diaphragm.

In Fig. 3 of the drawing there is shown a clamping arrangement in whichthe central as well as the peripheral portion of the diaphragm isclamped or compressed to thereby produce a sealing effect which willprevent the access of air to the lubricating material and therebymaintain the material indefinitely against deteriorationQ As alreadyindicated, the-amount of lubricating material employed may be very smalland may even be wholly omitted in certain cases. InFigJl of the drawingthere is shown a diaphragm -formed of a plurality of sheets offibrous-material such as paper, the sheets or disks being clamped intointimate superficial contact with each other,

without making use of either adhesive or lubricating material betweenthe disks.

What I claim is:

l. A diaphragm formed of a plurality of layers of mica with a lubricanttherebetween, the mica being clamped together at its periphery and alsonear the center to preventaccess of air to the lubricant.

2. A diaphragm formed of a plurality of layers of mica with Vaselinetherebetween, the mica being clamped together at-its periphery and alsonear the center to prevent access of air to the Vaseline.

3. A diaphragm for sound boxes comprising a plurality of layers ofnormally resonant material with a lubricant therebetween, whereby normalresonance is overcome, the layers of material bei-n clampecl 'togetherat their periphery and a o near the *center to prevent access of air'tothe lubricant 'Signed at Nantucket, in the countyio f Nantucket a-nd-State of Masaohusetts, this 13th "day of Septem-hery1920.

lemme-K 1B; D ELANQY.

